1. FIELD OF THE INVENTION
This invention relates to a light-sensitive copying material containing an O-quinone diazide compound as a light-sensitive component.
2. DESCRIPTION OF THE PRIOR ART
It is known that O-quinone diazide compounds decompose at the diazo group upon radiation with active rays to become carboxyl group-bearing compounds. When a copying layer containing an O-quinone diazide compound is imagewise exposed and then treated with an alkaline developer, therefore, the exposed area is removed and the non-exposed area remains as an image. Accordingly, an O-quinone diazide compound has lately become noted as a light-sensitive component of the so-called positive-positive type, in particular, as a light-sensitive copying composition for a printing original or as a photoresist composition for photoetching, for example, as disclosed in U.S. Pat. No. 3,181,461. These compositions comprise generally not only an O-quinone diazide compound but also an alkali-soluble resin such as a phenol-formaldehyde resin and a styrene-maleic anhydride copolymer to reinforce the image strength and to increase the film-forming properties, and can preferably be used in the form of a uniform composition, in addition, with additives such as dyes and plasticizers.
However, the O-quinone diazide-containing light-sensitive material of the prior art has the disadvantage that a considerable thickness, for example, 0.5 to 10 microns is necessary in order to obtain a sufficient image strength and thus a large amount of O-quinone diazide compound must be used. As a result the light sensitivity is low as a copying layer. Furthermore, the resin for increasing the image strength should be miscible with O-quinone diazide compounds and only a narrow selection of material is suitable. Therefore, the reinforcing of an image can not be advantageously carried out.